Conventional organic photosensors rely on the extraction of photogenerated charges for signal detection. Organic photosensitive materials typically show low efficiency because the photogenerated charges are not able to reach electrodes due to charge trapping and recombination. Generally, photosensors are devices with p-n junctions at which the photogenerated charges (i.e., electron-hole pairs) separate and drift toward the electrodes. However, because of severe recombination problems that exist in current organic photosensors, fewer photogenerated charges arrive at the electrodes, and therefore fewer photogenerated charges can be extracted. As a result, the photosensors exhibit decreased efficiency.
A charge map array may include an array of photosensors. Information can be extracted from the array of photosensors to create a charge map image. The operation of each of the photosensors in a charge map array conventionally depends on the total amount of photogenerated charges that can be extracted from the photosensors. The amount of photogenerated charges that can be extracted from the photosensors can be affected by defects in the photosensitive materials or other operational characteristics of the organic materials that are used. In other words, if some or all of the photosensors of the charge map array exhibit poor performance characteristics such as low efficiency, then line defects or point defects can appear in the charge map image.
While the use of organic photosensitive materials in charge mapping arrays provides certain benefits such as cost and flexibility over the use of non-organic materials, efficiency and accuracy of the charge map image may suffer as a result.